Loud speaker



March 20, 1934. A, EVENS 1,951,692

LOUD SPEAKER Filed April 12, 1933 2 Sheets-Sheet 1 Invenior Jlbi fflfyemi fiamm flllorney Patented Mar. 20, 1934 UNITED STATES PATENT OFFICE 2 Claims.

This invention appertains to new and useful improvements in loud speakers, such as are employed in conjunction with radio receivers.

The principal object of the present invention is to provide a loud speaker having a plurality of diaphragms for the purpose of affording reproduction in various tones.

Another important object of the invention is to provide a multiple diaphragm loud speaker wherein the parts are mounted in such a manner as to permit quick disassembling for the purpose of repair or replacement.

Various other important objects and advantages of the invention will become apparent to the reader of the following specification.

In the drawings:

Figure 1 represents a front elevational view of the novel speaker.

Figure 2 represents a vertical longitudinal sectional view through the speaker.

Figure 3 represents a cross sectional view taken substantially on line 3-3 of Figure 2.

Figure 4 represents a side elevational View of one of the diaphragms and its voice coil.

Referring to the drawings wherein like numerals designate like parts, itcan be seen that the numeral 5 represents the usual electro-magnet having the elongated soft iron core 6, the same being provided with a projecting end portion consisting of the areas 7, 8 and 9. The areas 8 and 9 are reductions of the core proper, the area 8 being of less diameter than the core proper, while the area 9 is of less diameter than the area 8.

Numeral 10 represents a housing for the coil 5 and this is secured to the pole piece 11 by tie rods 12 and connector plates 13, as in the manner substantially shown in Figure 2.

The pole piece 11 has the speaker shell 14 extending in a flared manner therefrom and being provided at its outer edge with an outstanding flange 15. At this mentioned end portion and at the inner side of the shell 14 is an annular shoulder 16, the like of which is also provided on the conical walls 17 and 18 to which the enlarged edge portions of the diaphragms 19-20 are secured, as at 21, the outer edge portion of the diaphragm 22 being secured to the shoulder 16 on the casing 14. The reduced end portion of the diaphragm 22 has its voice coil 24 located within the pole piece 11, while the voice coil 25 of the diaphragm 19 is located within the pole piece 26 at the reduced end of the wall or cone 17.

The voice coil 27 of the diaphragm 20 is located within the pole piece of the cone 18, this pole piece being denoted by numeral 28. One end of each pole piece has its air space closed by a centering ring 29, while the flexible suspending means 30 for the corresponding diaphragm is located at the opposite side of the pole piece.

The innermost diaphragm 20 is secured by a plate 30 bearing against the inner side thereof and attached as at 31 to the outer end of the core area 9.

The conical walls 1'? and 18 have outstanding flanges 32 and 33 which are secured to the outstanding fiange 15 of the shell 14 by bolts and nuts 34.

In the use of this novel speaker, a suitable switch may be employed whereby only one of the diaphragms or more than one can be operated simultaneously, to the end that a single bass, intermediate or treble tone can be obtained or a combination of these tones.

While the foregoing specification sets forth the invention in specific terms, it is to be understood that numerous changes in the shape, size and materials may be resorted to without departing from the spirit and scope of the invention as claimed hereinafter.

Having described the invention, what is claimed as new is:-

1. A radio loud speaker comprising a plurality of conical-shaped diaphragms, one mounted within the other and each provided with a pole piece at its apex portion, a single electro-magnet provided with an elongated core member projecting longitudinally through the said pole pieces, the said pole pieces being arranged in extended relation with respect to each other and along the longitudinal extent of the said core, said pole pieces being spaced from the said core to provide air spaces and voice coils on the said diaphragms disposed within the said air spaces.

2. A radio loud speaker comprising a plurality of conical-shaped diaphragms, one mounted within the other and each provided with a pole piece at its apex portion, a single electro-magnet provided with an elongated core member projecting longitudinally through the said pole pieces, the said pole pieces being arranged in extended relation with respect to each other and along the longitudinal extent of the said core, said pole pieces being spaced from the said core to provide air spaces, voice coils on the said diaphragms disposed within the said air spaces, the said diaphragms gradually decreasing in size from the outermost to the innermost, the said core member being provided with reduced portions, the said pole pieces being reduced in size from the outermost diaphragm to the innermost to correspond with the reduced portions of the core member.

ALBERT M. EVENS. 

